A micro-machined piezoelectric transducer is a device that achieves conversion from mechanical to electrical energy or vice versa via a piezoelectric effect of a piezoelectric material, and can be simultaneously used as a transmitter and a receiver and therefore has a huge potential for development.
US 20160172577, which is a co-pending application of the applicant of the disclosure, discloses a method for fabricating a piezoelectric transducer. The piezoelectric transducer thus fabricated includes a substrate, a pair of patterned electrodes formed on the substrate, and a piezoelectric membrane formed on a positive electrode of the pair of patterned electrodes via a process which integrates a patterning process with a polarization process. A pair of the piezoelectric transducers may be used as a micro-machined transceiver of a biosensor for detection of an amount of an analyte such as ractopamine, benzylpenicillin, doxycycline, and the like. The sensing mechanism is based on a piezoelectric response change due to absorption of the analyte on the piezoelectric membrane.
However, since the piezoelectric membrane is formed on one of the positive and negative electrodes via in-situ deposition of a piezoelectric material, such as a piezoelectric polymer, impurities which may be contained in a piezoelectric suspension for forming the piezoelectric membrane will attach to the piezoelectric membrane thus formed, leading to inaccurate detection.